Resistor and process of making same



June 19, 1934. R. D. MCDILL RESISTOR AND PROCESS OF MAKING SAME Filed Jan. 4, 14953 wva/MM 2 REX D. Me/L1.

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Patented June 19, 1934` UNITED lSTATES PATENT lOFFICE 1,963,554 nEsIs'roR AND rnoCE'ss or MAKING SAME Rex D. McDill, Cleveland, Ohio Application January 4, 1933, Serial No. 650,147 13 Claims. (Cl. 21H-'16) The object of my invention is to provide an imsoon wears out and is noisy and is not uniform proved radio resistor and a novel process of manin its resistance, and further the carbon type ufacturing same. I attain the objects of my inhas anegative voltage coeiilcient, and the straight vention by the means illustrated in the accomwound wire type has a positive coemcient while f panying drawing, in which mine seems to equalize. 60 Figure 1 is a face or plan view of a. strip of It is not essential to treat the threads before material made in accordance with my invenweaving as the material can be cut into strips tion; and dipped after being woven. In such case the Fig. 2 is a section on line 2-2 of Fig. l; treating material covers the entire fabric, both 13 Fig. 3 is a section on yline 3--3 of Fig. 1; threads and wire. In treating the following 65 Fig. 4 is a section similar to Fig. 3 but with the methods may be employed. The material can coating applied to the woven material; be dipped in the graphite solution or carbon ma- Fig. 5 is a similar detail view with the termiterial in suspension in liquid form or a combinanal soldered to the material; tion of both depending upon the resistance del5 Fig. 6 is a perspective view of the completed sired in the finished product and the quan- 70 device; and tities of each used and the strength of the so1u-v Fig. 'I is a perspective view of a modified form tion as compared to its solvent content.v The of the invention. material is then thoroughly dried to drive out Like numerals designate like parts in each of all moisture. It can then be painted with a 2O the several views. pyroxylin enamel like Duco or the preferred way 75 Referring to the accompanying drawing, I prois to paint it with phenolic formaldehyde (bakelite vide warp threads l made from linen or other resinoid) product in a suitable solvent such as textile material which is treated before weaving acetone, then dry oi the solvent at a low temby passing the material through colloidal graphite perature, and finally polymerize the resinoid by in aqueous solution, or carbon of the conductive baking at a higher temperature. If the resis 80 resistive type, or a mixture of both; and then tors are for potentiometers or rheostats of the drying the thread. When the warp threads are circular type a split ring is formed before the dried the material is woven by passing wire bakelite is baked on as it would crack if bent threads 2 through the threads as a weft. The after baking. To insure complete moisture proofentire weave is about thirty inches wide and the ing of the article, an intermediate step can be 86 fabric for this purpose is woven about 40 mesh. taken by applying a solution of parafiine and The Carbon 0I' graphite threads have B negative gasoline to the dried carbon treated fabric and voltage coefficient as in all resistors of the carbon then evaporate the solvent before applying the type but the wire, especially nichrome wire which Duco or balrelite.

Preferably iS Used aS the weft, has a positive volt- Terminals or pig tails 'l are either soldered to 00 age coefficient so that the finished resistor has the ends of the resistors 8 before baking, or treat,- as near a voltage-coecient level as it is posing 'with the Duco or bakelite. sible t0 make 3 Cheap TeSStOl'. Referring to Fig. '7 of the drawing, there is il- I provide terminals 5 which are soldered at lustrateda variable resistor 9 in which the wires 40 6, the terminals having the usual apertures '7, 2 protrude out through the enamel 'in order to 95 as shown in Fig. 5. To facilitate soldering the form electrical contact with the sliding Contact terminals, phosphor bronze Wire tinned is used member 10 which carries the terminal ll provid as a weft. ed with aperture 12.

I next take the woven material and impregnate In some cases I have mixed carbon and/or it with lacquer or enamel-like bakelite 3 in which graphite with the enamel before applying and it 100 there is in suspension graphite and carbon which also makes a very good resistor. is high resistant material. After that is entire- The material can be dipped in the graphite ly dried I coat it again with dielectric varnish solution or carbon material in suspension in liqor enamel 4 and then cut the strip lengthwise uid form or a combination of both depending down the center as indicated by the two sets of upon the resistance desired in the iinished product 105 lines designated awa in Fig. l. This can be and the quantities of each used and the strength formed into a circle or strip and used as a rheoof the solution as compared to its solvent constat or potentiometer. This construction has a tent. The material is then thoroughly dried to distinct advantage over the type where the slide drive out all moisture. It can then be painted Contact rubs on the carbon because that type with a pyroxylin enamel like Duco o r the preno ferred way is to paint it with phenolic formaldehyde (bakelite resinoid) product in a suitable solvent such as acetone, then dry off the solvent at a low temperature and finally polymerize the resinoid by baking at a higher temperature. If the resistors are for potentiometers or rheostats of the circular type a split ring is formed before the bakelite is baked on as it would crack if bent after baking. To insure complete moisture proofing of the'article an intermediate step can be taken by applying a solution of paraiilne and gasoline to the dried carbon treated fabric and then evaporate the solvent before applying the Duco or bakelite. Terminals or pig tails 'I are either soldered to the ends of the resistors 8 before baking, or treating with the Duco or bakelite.

1. The process of manufacturing a resistor consisting in treating Warp threads of linen or other textile material by passing the material through colloidal graphite in aqueous solution, weaving Wire Woof threads through the aforesaid warp threads, impregnating the woven material with lacquer, coating the product with a dielectric varnish or enamel, and cutting the material lengthwise into suitable strips for use as a rheostat or potentiometer. 2. The process of manufacturing a resistor consisting in treating warp threads of linen or other textile material by passing the material through colloidal graphite in aqueous solution, weaving wire Woof threads through the aforesaid Warp threads, impregnating the woven material with high resistant material, coating the product with a dielectric varnish or enamel, and cutting the material lengthwise into suitable strips for use as a rheostat or potentiometer. Y

3. The process of manufacturing a resistor consisting in treating warp threads of linen or other textile material by passing the material through carbon of the conductive resistive type, weaving Wire Woof threads through the aforesaid warp threads, impregnating the woven material with lacquer, coating the product with a dielectric varnish or enamel, and cutting the material length- Wise into suitable strips for use as a rheostat or potentiometer. l

4. The process of manufacturing a resistor consisting in treating Warp threads of linen or other textile material by passing the material through a mixture of colloidal graphite in aqueous solution and carbon of the conductive resistive type, weaving Wire Woof threads through the aforesaid Warp threads, impregnating the woven material with lacquer, coating the product with a dielectric varnish or enamel, and cutting the material lengthwise into suitable strips for use as a rheostat or potentiometer.

5. The process of manufacturing a resistor consisting in weaving Wire Woof threads through warp threads of suitable textile material, dipping the completed fabric in graphite solution, drying the material, and painting the material with a suitable enamel.

6. The process of manufacturing a resistor consisting in weaving wire Woof threads through Warp threads of suitable textile material, dipping the completed fabric in graphite solution, drying the material, painting the material with phenolic formaldehyde in a suitable solvent such as acetone, drying ofi the solvent at a low temperature, and finally polymerizing the resinoid by baking at a higher'temperature.

7. The process of manufacturing a resistor consisting in weaving wire Woof threads through Warp threads of suitable textile material, dipping the completed fabric in graphite solution, drying the material, applying a moisture proof coating of a solution of parafine and gasoline to the dry carbon-treated fabric, evaporating the solvent, and painting the material with a suitable enamel.

8. The process oi manufacturing a resistor consisting in Weaving Wire Woof threads through warp threads of suitable textile material, dipping the completed fabric in graphite solution, drying the material, painting the material with phenolic formaldehyde in a suitable solvent such as acetone, drying off the solvent at a low temperature, applying a moisture proof coating of a solution of parafiine and gasoline to the dry carbon-treated fabric, evaporating the solvent, and finally polymerizing the resinoid by baking at a higher temperature.

9. The process of `manufacturing a resistor consisting in weaving wire Woof threads through Warp threads of suitable textile material, dipping the completed fabric in graphite solution, drying the material, painting the material with phenolic formaldehyde in a suitable solvent such as acetone, drying off the solvent at a low temperature-forming a split ring, and finally polymerizing the resinoid by baking at a higher temperature.

10. The process of manufacturing a resistor vconsisting in weaving wire Woof threads through Warp threads of suitable textile material, dipping the completed fabric in graphite solution, drying the material, painting the material with phenolic formaldehyde in a suitable solvent such as acetone, drying off the solvent at a low temperature forming a split ring, and applying a moisture proof coating of a solution of parafilne and gasoline to the dry carbon-treated fabric, evaporating the solvent, and finally polymerizing the resinoid by baking at a higher temperature.

11. A resistor consisting of fabric woven from warp threads of textile material and Woof threads of wire, a coating of high resistant material, and an outer coating of lacquer covering said rst mentioned coating.

12. A resistor consisting of fabric woven from warp threads of textile material and Woof threads of wire, a coating of high resistant mateli-al, and an outer coating of lacquer covering said first mentioned coating, terminals soldered to the woven fabric at each end thereof.

13. A resistor consisting of fabric woven from warp threads of textile material and Woof threads of Wire, a coating of high resistant material and an outer coating of lacquer covering said rst mentioned coating, one edge of the fabric having the ends of the wires of the fabric exposed, a longitudinally slidable contact member mounted on said edge portion of the fabric, and a terminal soldered to one end of the fabric.

REX D. MCDILL. 

